quote:Roose was one of the first to know. So it is very possible he found out then instructed his son to sack Winterfell. His plans with Tywin and the Frey's could have been made along with his plans to replace the Starks in Winterfell.

Seems likely. Though I've always sort of believed that Roose was always in league with Twyin from the beginning. Would explain him holding back troops at the Green Fork and that the Ironborn attack of Winterfell was the ultimate opportunity. What happened with Robb and Jeyne was just what Roose needed to inact his final plan, knowing the Frey's would be pissed.